Methods for making leads with segmented electrodes for electrical stimulation systems

ABSTRACT

One embodiment is a stimulation lead including a lead body comprising a longitudinal surface, a distal end, and a proximal end; and multiple electrodes disposed along the longitudinal surface of the lead body near the distal end of the lead body. The multiple electrodes include multiple segmented electrodes. At least a first portion of the lead body, proximal to the electrodes, is transparent or translucent and at least a second portion of the lead body, separating two or more of the segmented electrodes, is opaque so that the segmented electrodes separated by the second portion of the lead body are visually distinct. Alternatively or additionally, the stimulation lead can include an indicator ring, a stripe, a groove, or a marking aligned with one or more of the segmented electrodes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/369,013 filed Feb. 8, 2012, now U.S. Pat. No. 8,560,085, which claimsthe benefit under 35 U.S.C. §119(e) of U.S. Provisional PatentApplication Ser. No. 61/440,533 filed on Feb. 8, 2011, all of which areincorporated herein by reference.

FIELD

The invention is directed to the area of electrical stimulation systemsand methods of making and using the systems. The present invention isalso directed to electrical stimulation leads with multiple sets ofsegmented electrodes, as well as methods of making and using thesegmented electrodes, leads, and electrical stimulation systems.

BACKGROUND

Electrical stimulation can be useful for treating a variety ofconditions. Deep brain stimulation can be useful for treating, forexample, Parkinson's disease, dystonia, essential tremor, chronic pain,Huntington's Disease, levodopa-induced dyskinesias and rigidity,bradykinesia, epilepsy and seizures, eating disorders, and mooddisorders. Typically, a lead with a stimulating electrode at or near atip of the lead provides the stimulation to target neurons in the brain.Magnetic resonance imaging (“MRI”) or computerized tomography (“CT”)scans can provide a starting point for determining where the stimulatingelectrode should be positioned to provide the desired stimulus to thetarget neurons.

After the lead is implanted into a patient's brain, electrical stimuluscurrent can be delivered through selected electrodes on the lead tostimulate target neurons in the brain. Typically, the electrodes areformed into rings disposed on a distal portion of the lead. The stimuluscurrent projects from the ring electrodes equally in every direction.Because of the ring shape of these electrodes, the stimulus currentcannot be directed to one or more specific positions around the ringelectrode (e.g., on one or more sides, or points, around the lead).Consequently, undirected stimulation may result in unwanted stimulationof neighboring neural tissue, potentially resulting in undesired sideeffects.

BRIEF SUMMARY

One embodiment is a stimulation lead including a lead body comprising alongitudinal surface, a distal end, and a proximal end; and multipleelectrodes disposed along the longitudinal surface of the lead body nearthe distal end of the lead body. The multiple electrodes includemultiple segmented electrodes. Optionally, at least some of thesegmented electrodes are formed into a first set of segmented electrodeshaving at least two of the segmented electrodes disposed around acircumference of the lead at a first longitudinal position along thelead, and a second set of segmented electrodes having at least two ofthe segmented electrodes disposed around a circumference of the lead ata second longitudinal position along the lead. At least a first portionof the lead body, proximal to the electrodes, is transparent ortranslucent and at least a second portion of the lead body, separatingtwo or more of the segmented electrodes, is opaque so that the segmentedelectrodes separated by the second portion of the lead body are visuallydistinct.

Another embodiment is a stimulation lead including a lead body having alongitudinal surface, a distal end, and a proximal end; and multipleelectrodes disposed along the longitudinal surface of the lead body nearthe distal end of the lead body. The multiple electrodes includemultiple segmented electrodes. Optionally, at least some of thesegmented electrodes are formed into a first set of segmented electrodeshaving at least two of the segmented electrodes disposed around acircumference of the lead at a first longitudinal position along thelead. The stimulation lead also includes an indicator ring disposeddistal to the electrodes and marked to indicate a one of the segmentedelectrodes.

Yet another embodiment is a stimulation lead including a lead bodyhaving a longitudinal surface, a distal end, and a proximal end; andmultiple electrodes disposed along the longitudinal surface of the leadbody near the distal end of the lead body. The multiple electrodesinclude multiple segmented electrodes. At least some of the segmentedelectrodes are formed into a first set of segmented electrodes having atleast two of the segmented electrodes disposed around a circumference ofthe lead at a first longitudinal position along the lead, and a secondset of segmented electrodes having at least two of the segmentedelectrodes disposed around a circumference of the lead at a secondlongitudinal position along the lead. The first and second sets ofsegmented electrodes are adjacent to each other and aligned with eachother. The stimulation lead also includes a stripe extending along atleast a distal portion of the lead body and aligned with a one of thesegmented electrodes in each of the first and second sets of segmentedelectrodes.

A further embodiment is a stimulation lead including a lead bodycomprising a longitudinal surface, a distal end, and a proximal end; andmultiple electrodes disposed along the longitudinal surface of the leadbody near the distal end of the lead body. The multiple electrodesinclude multiple segmented electrodes. At least some of the segmentedelectrodes are formed into a first set of segmented electrodes having atleast two of the segmented electrodes disposed around a circumference ofthe lead at a first longitudinal position along the lead, and a secondset of segmented electrodes having at least two of the segmentedelectrodes disposed around a circumference of the lead at a secondlongitudinal position along the lead. The first and second sets ofsegmented electrodes are adjacent to each other and aligned with eachother. The stimulation lead also includes a groove formed in the leadbody and extending along at least a distal portion of the lead body. Thegroove is aligned with a one of the segmented electrodes in each of thefirst and second sets of segmented electrodes.

Another embodiment is a stimulation lead including a lead bodycomprising a longitudinal surface, a distal end, and a proximal end; andmultiple electrodes disposed along the longitudinal surface of the leadbody near the distal end of the lead body. The multiple electrodesinclude multiple segmented electrodes. At least some of the segmentedelectrodes are formed into a first set of segmented electrodes having atleast two of the segmented electrodes disposed around a circumference ofthe lead at a first longitudinal position along the lead, and a secondset of segmented electrodes having at least two of the segmentedelectrodes disposed around a circumference of the lead at a secondlongitudinal position along the lead. The first and second sets ofsegmented electrodes are adjacent to each other and aligned with eachother. The stimulation lead also includes a marking disposed at or nearthe distal end of the lead body and distal to all of the electrodes. Themarking is aligned with a one of the segmented electrodes in each of thefirst and second sets of segmented electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified.

For a better understanding of the present invention, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, wherein:

FIG. 1 is a schematic side view of one embodiment of a device for brainstimulation, according to the invention;

FIG. 2 is a schematic perspective view of one embodiment of a portion ofa lead having a plurality of segmented electrodes, according to theinvention;

FIG. 3A is a perspective view of a third embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention;

FIG. 3B is a perspective view of a fourth embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention;

FIG. 4 is a schematic diagram of radial current steering along variouselectrode levels along the length of a lead, according to the invention;

FIG. 5 is a perspective view of another embodiment of a portion of alead having a plurality of segmented electrodes arranged in a staggeredorientation, according to the invention;

FIG. 6A is a perspective view of an embodiment of a portion of a leadhaving a plurality of segmented electrodes and opaque material betweenthe electrodes, according to the invention;

FIG. 6B is a perspective view of another embodiment of a portion of alead having a plurality of segmented electrodes and opaque materialbetween the electrodes and at a tip of the lead, according to theinvention;

FIG. 6C is a perspective view of a third embodiment of a portion of alead having a plurality of segmented electrodes and opaque materialbetween the electrodes, at a distal tip of the lead, and proximal to theelectrodes, according to the invention;

FIG. 6D is a perspective view of a fourth embodiment of a portion of alead having a plurality of segmented electrodes and opaque materialbetween the sets of segmented electrodes, according to the invention;

FIG. 6E is a perspective view of another embodiment of a portion of alead having a plurality of segmented electrodes and opaque materialbetween the segmented electrodes of each set, according to theinvention;

FIG. 7A is a perspective view of one embodiment of a portion of a leadhaving a plurality of segmented electrodes and a marker at a distal tipof the lead, according to the invention;

FIG. 7B is a perspective view of another embodiment of a portion of alead having a plurality of segmented electrodes and a marker at a distaltip of the lead, according to the invention;

FIG. 8A is a perspective view of one embodiment of a portion of a leadhaving a plurality of segmented electrodes and a stripe extending alongat least a distal portion of the lead, according to the invention;

FIG. 8B is a perspective view of another embodiment of a portion of alead having a plurality of segmented electrodes and a stripe extendingalong a distal portion of the lead, according to the invention;

FIG. 8C is a perspective view of a third embodiment of a portion of alead having a plurality of segmented electrodes and a stripe extendingalong at least a distal portion of the lead, according to the invention;

FIG. 8D is a perspective view of a fourth embodiment of a portion of alead having a plurality of segmented electrodes and a stripe extendingalong a portion of the lead proximal to the electrodes, according to theinvention;

FIG. 8E is a perspective view of a fifth embodiment of a portion of alead having a plurality of segmented electrodes and a stripe extendingbetween electrodes at a distal portion of the lead, according to theinvention;

FIG. 8F is a perspective view of a sixth embodiment of a portion of alead having a plurality of segmented electrodes and a stripe extendingalong portions of the lead proximal and distal to the electrodes,according to the invention;

FIG. 9 is a perspective view of one embodiment of a portion of a leadhaving a plurality of segmented electrodes and an indicator ring on adistal portion of the lead, according to the invention;

FIG. 10A is a cross-sectional view of one embodiment of a portion of alead body having a groove or notch, according to the invention; and

FIG. 10B is a perspective view of another embodiment of a portion of alead body having a groove or notch, according to the invention.

DETAILED DESCRIPTION

The invention is directed to the area of electrical stimulation systemsand methods of making and using the systems. The present invention isalso directed to forming electrical stimulation leads with multiple setsof segmented electrodes, as well as methods of making and using thesegmented electrodes, leads, and electrical stimulation systems.

A lead for deep brain stimulation may include stimulation electrodes,recording electrodes, or a combination of both. At least some of thestimulation electrodes, recording electrodes, or both are provided inthe form of segmented electrodes that extend only partially around thecircumference of the lead. These segmented electrodes can be provided insets of electrodes, with each set having electrodes radially distributedabout the lead at a particular longitudinal position.

A practitioner may determine the position of the target neurons usingthe recording electrode(s) and then position the stimulationelectrode(s) accordingly without removal of a recording lead andinsertion of a stimulation lead. In some embodiments, the sameelectrodes can be used for both recording and stimulation. In someembodiments, separate leads can be used; one with recording electrodeswhich identify target neurons, and a second lead with stimulationelectrodes that replaces the first after target neuron identification. Alead may include recording electrodes spaced around the circumference ofthe lead to more precisely determine the position of the target neurons.In at least some embodiments, the lead is rotatable so that thestimulation electrodes can be aligned with the target neurons after theneurons have been located using the recording electrodes. Forillustrative purposes, the leads are described herein relative to usefor deep brain stimulation, but it will be understood that any of theleads can be used for applications other than deep brain stimulation.

Deep brain stimulation devices and leads are described in, for example,U.S. Pat. No. 7,809,446 (“Devices and Methods For Brain Stimulation”),U.S. Patent Application Publication No. 2010/0076535 A1 (“Leads WithNon-Circular-Shaped Distal Ends For Brain Stimulation Systems andMethods of Making and Using”), U.S. Patent Application Publication2007/0150036 A1 (“Stimulator Leads and Methods For Lead Fabrication”),U.S. patent application Ser. No. 12/177,823 (“Lead With Transition andMethods of Manufacture and Use”), U.S. Patent Application PublicationNo. 2009/0276021 A1 (“Electrodes For Stimulation Leads and Methods ofManufacture and Use”), U.S. Pat. No. 8,473,061 (“Deep Brain StimulationCurrent Steering with Split Electrodes”), U.S. Patent ApplicationPublication No. 2009/0187222 A1, and U.S. Patent Application PublicationNo. 2012/0165911 A1. Each of these references is incorporated herein byreference.

FIG. 1 illustrates one embodiment of a device 100 for brain stimulation.The device includes a lead 110, a plurality of electrodes 125 disposedat least partially about a circumference of the lead 110, a plurality ofterminals 135, a connector 130 for connection of the electrodes to acontrol unit, and a stylet 140 for assisting in insertion andpositioning of the lead in the patient's brain. The stylet 140 can bemade of a rigid material. Examples of suitable materials for the styletinclude, but are not limited to, tungsten, stainless steel, and plastic.The stylet 140 may have a handle 150 to assist insertion into the lead110, as well as rotation of the stylet 140 and lead 110. The connector130 fits over a proximal end of the lead 110, preferably after removalof the stylet 140.

The control unit (not shown) is typically an implantable pulse generatorthat can be implanted into a patient's body, for example, below thepatient's clavicle area. The pulse generator can have eight stimulationchannels which may be independently programmable to control themagnitude of the current stimulus from each channel. In some cases thepulse generator may have more than eight stimulation channels (e.g.,16-, 32-, or more stimulation channels). The control unit may have one,two, three, four, or more connector ports, for receiving the pluralityof terminals 135 at the proximal end of the lead 110.

In one example of operation, access to the desired position in the braincan be accomplished by drilling a hole in the patient's skull or craniumwith a cranial drill (commonly referred to as a burr), and coagulatingand incising the dura mater, or brain covering. The lead 110 can beinserted into the cranium and brain tissue with the assistance of thestylet 140. The lead 110 can be guided to the target location within thebrain using, for example, a stereotactic frame and a microdrive motorsystem. In some embodiments, the microdrive motor system can be fully orpartially automatic. The microdrive motor system may be configured toperform one or more the following actions (alone or in combination):insert the lead 110, retract the lead 110, or rotate the lead 110.

In some embodiments, measurement devices coupled to the muscles or othertissues stimulated by the target neurons, or a unit responsive to thepatient or clinician, can be coupled to the control unit or microdrivemotor system. The measurement device, user, or clinician can indicate aresponse by the target muscles or other tissues to the stimulation orrecording electrode(s) to further identify the target neurons andfacilitate positioning of the stimulation electrode(s). For example, ifthe target neurons are directed to a muscle experiencing tremors, ameasurement device can be used to observe the muscle and indicatechanges in tremor frequency or amplitude in response to stimulation ofneurons. Alternatively, the patient or clinician may observe the muscleand provide feedback.

The lead 110 for deep brain stimulation can include stimulationelectrodes, recording electrodes, or both. In at least some embodiments,the lead 110 is rotatable so that the stimulation electrodes can bealigned with the target neurons after the neurons have been locatedusing the recording electrodes.

Stimulation electrodes may be disposed on the circumference of the lead110 to stimulate the target neurons. Stimulation electrodes may bering-shaped so that current projects from each electrode equally inevery direction from the position of the electrode along a length of thelead 110. Ring electrodes, however, typically do not enable stimuluscurrent to be directed to only one side of the lead. Segmentedelectrodes, however, can be used to direct stimulus current to one side,or even a portion of one side, of the lead. When segmented electrodesare used in conjunction with an implantable pulse generator thatdelivers constant current stimulus, current steering can be achieved tomore precisely deliver the stimulus to a position around an axis of thelead (i.e., radial positioning around the axis of the lead).

To achieve current steering, segmented electrodes can be utilized inaddition to, or as an alternative to, ring electrodes. Though thefollowing description discusses stimulation electrodes, it will beunderstood that all configurations of the stimulation electrodesdiscussed may be utilized in arranging recording electrodes as well.

FIG. 2 illustrates one embodiment of a distal portion of a lead 200 forbrain stimulation. The lead 200 includes a lead body 210, one or moreoptional ring electrodes 220, and a plurality of sets of segmentedelectrodes 230. The lead body 210 can be formed of a biocompatible,non-conducting material such as, for example, a polymeric material.Suitable polymeric materials include, but are not limited to, silicone,polyurethane, polyurea, polyurethane-urea, polyethylene, or the like.Once implanted in the body, the lead 200 may be in contact with bodytissue for extended periods of time. In at least some embodiments, thelead 200 has a cross-sectional diameter of no more than 1.5 mm and maybe in the range of 1 to 1.5 mm. In at least some embodiments, the lead200 has a length of at least 10 cm and the length of the lead 200 may bein the range of 25 to 70 cm.

The electrodes may be made using a metal, alloy, conductive oxide, orany other suitable conductive biocompatible material. Examples ofsuitable materials include, but are not limited to, platinum, platinumiridium alloy, iridium, titanium, tungsten, palladium, palladiumrhodium, or the like. Preferably, the electrodes are made of a materialthat is biocompatible and does not substantially corrode under expectedoperating conditions in the operating environment for the expectedduration of use.

Each of the electrodes can either be used or unused (OFF). When theelectrode is used, the electrode can be used as an anode or cathode andcarry anodic or cathodic current. In some instances, an electrode mightbe an anode for a period of time and a cathode for a period of time.

Stimulation electrodes in the form of ring electrodes 220 may bedisposed on any part of the lead body 210, usually near a distal end ofthe lead 200. In FIG. 2, the lead 200 includes two ring electrodes 220.Any number of ring electrodes 220 may be disposed along the length ofthe lead body 210 including, for example, one, two three, four, five,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen, sixteen or more ring electrodes 220. It will be understood thatany number of ring electrodes may be disposed along the length of thelead body 210. In some embodiments, the ring electrodes 220 aresubstantially cylindrical and wrap around the entire circumference ofthe lead body 210. In some embodiments, the outer diameters of the ringelectrodes 220 are substantially equal to the outer diameter of the leadbody 210. The length of the ring electrodes 220 may vary according tothe desired treatment and the location of the target neurons. In someembodiments the length of the ring electrodes 220 are less than or equalto the diameters of the ring electrodes 220. In other embodiments, thelengths of the ring electrodes 220 are greater than the diameters of thering electrodes 220.

Deep brain stimulation leads may include one or more sets of segmentedelectrodes. Segmented electrodes may provide for superior currentsteering than ring electrodes because target structures in deep brainstimulation are not typically symmetric about the axis of the distalelectrode array. Instead, a target may be located on one side of a planerunning through the axis of the lead. Through the use of a radiallysegmented electrode array (“RSEA”), current steering can be performednot only along a length of the lead but also around a circumference ofthe lead. This provides precise three-dimensional targeting and deliveryof the current stimulus to neural target tissue, while potentiallyavoiding stimulation of other tissue.

In FIG. 2, the lead 200 is shown having a plurality of segmentedelectrodes 230. Any number of segmented electrodes 230 may be disposedon the lead body 210 including, for example, one, two three, four, five,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen, sixteen or more segmented electrodes 230. It will be understoodthat any number of segmented electrodes 230 may be disposed along thelength of the lead body 210.

The segmented electrodes 230 may be grouped into sets of segmentedelectrodes, where each set is disposed around a circumference of thelead 200 at a particular longitudinal portion of the lead 200. The lead200 may have any number of segmented electrodes 230 in a given set ofsegmented electrodes. The lead 200 may have one, two, three, four, five,six, seven, eight, or more segmented electrodes 230 in a given set. Inat least some embodiments, each set of segmented electrodes 230 of thelead 200 contains the same number of segmented electrodes 230. Thesegmented electrodes 230 disposed on the lead 200 may include adifferent number of electrodes than at least one other set of segmentedelectrodes 230 disposed on the lead 200.

The segmented electrodes 230 may vary in size and shape. In someembodiments, the segmented electrodes 230 are all of the same size,shape, diameter, width or area or any combination thereof. In someembodiments, the segmented electrodes 230 of each circumferential set(or even all segmented electrodes disposed on the lead 200) may beidentical in size and shape.

Each set of segmented electrodes 230 may be disposed around thecircumference of the lead body 210 to form a substantially cylindricalshape around the lead body 210. The spacing between individualelectrodes of a given set of the segmented electrodes may be the same,or different from, the spacing between individual electrodes of anotherset of segmented electrodes on the lead 200. In at least someembodiments, equal spaces, gaps or cutouts are disposed between eachsegmented electrode 230 around the circumference of the lead body 210.In other embodiments, the spaces, gaps or cutouts between the segmentedelectrodes 230 may differ in size or shape. In other embodiments, thespaces, gaps, or cutouts between segmented electrodes 230 may be uniformfor a particular set of the segmented electrodes 230, or for all sets ofthe segmented electrodes 230. The sets of segmented electrodes 230 maybe positioned in irregular or regular intervals along a length the leadbody 210.

Conductor wires that attach to the ring electrodes 220 or segmentedelectrodes 230 extend along the lead body 210. These conductor wires mayextend through the material of the lead 200 or along one or more lumensdefined by the lead 200, or both. The conductor wires are presented at aconnector (via terminals) for coupling of the electrodes 220, 230 to acontrol unit (not shown).

When the lead 200 includes both ring electrodes 220 and segmentedelectrodes 230, the ring electrodes 220 and the segmented electrodes 230may be arranged in any suitable configuration. For example, when thelead 200 includes two sets of ring electrodes 220 and two sets ofsegmented electrodes 230, the ring electrodes 220 can flank the two setsof segmented electrodes 230 (see e.g., FIG. 2). Alternately, the twosets of ring electrodes 220 can be disposed proximal to the two sets ofsegmented electrodes 230 (see e.g., FIG. 3A), or the two sets of ringelectrodes 220 can be disposed distal to the two sets of segmentedelectrodes 230 (see e.g., FIG. 3B). It will be understood that otherconfigurations are possible as well (e.g., alternating ring andsegmented electrodes, or the like).

By varying the location of the segmented electrodes 230, differentcoverage of the target neurons may be selected. For example, theelectrode arrangement of FIG. 3A may be useful if the physiciananticipates that the neural target will be closer to a distal tip of thelead body 210, while the electrode arrangement of FIG. 3B may be usefulif the physician anticipates that the neural target will be closer to aproximal end of the lead body 210.

Any combination of ring electrodes 220 and segmented electrodes 230 maybe disposed on the lead 200. For example, the lead may include a firstring electrode, two sets of segmented electrodes, each set formed ofthree segmented electrodes 230, and a final ring electrode at the end ofthe lead. This configuration may simply be referred to as a 1-3-3-1configuration. It may be useful to refer to the electrodes with thisshorthand notation. Thus, the embodiment of FIG. 3A may be referred toas a 1-1-3-3 configuration, while the embodiment of FIG. 3B may bereferred to as a 3-3-1-1 configuration. Other eight-electrodeconfigurations include, for example, a 2-2-2-2 configuration, where foursets of segmented electrodes are disposed on the lead, and a 4-4configuration, where two sets of segmented electrodes, each having foursegmented electrodes 230 are disposed on the lead. In some embodiments,the lead includes 16 electrodes. Possible configurations for a16-electrode lead include, but are not limited to 4-4-4-4; 8-8;3-3-3-3-3-1 (and all rearrangements of this configuration); and2-2-2-2-2-2-2-2.

FIG. 4 is a schematic diagram to illustrate radial current steeringalong various electrode levels along the length of the lead 200. Whileconventional lead configurations with ring electrodes are only able tosteer current along the length of the lead (the z-axis), the segmentedelectrode configuration is capable of steering current in the x-axis,y-axis as well as the z-axis. Thus, the centroid of stimulation may besteered in any direction in the three-dimensional space surrounding thelead 200. In some embodiments, the radial distance, r, and the angle θaround the circumference of the lead 200 may be dictated by thepercentage of anodic current (recognizing that stimulation predominantlyoccurs near the cathode, although strong anodes may cause stimulation aswell) introduced to each electrode. In at least some embodiments, theconfiguration of anodes and cathodes along the segmented electrodesallows the centroid of stimulation to be shifted to a variety ofdifferent locations along the lead 200.

As can be appreciated from FIG. 4, the centroid of stimulation can beshifted at each level along the length of the lead 200. The use ofmultiple sets of segmented electrodes at different levels along thelength of the lead allows for three-dimensional current steering. Insome embodiments, the sets of segmented electrodes are shiftedcollectively (i.e., the centroid of simulation is similar at each levelalong the length of the lead). In at least some other embodiments, eachset of segmented electrodes is controlled independently. Each set ofsegmented electrodes may contain two, three, four, five, six, seven,eight or more segmented electrodes. It will be understood that differentstimulation profiles may be produced by varying the number of segmentedelectrodes at each level. For example, when each set of segmentedelectrodes includes only two segmented electrodes, uniformly distributedgaps (inability to stimulate selectively) may be formed in thestimulation profile. In some embodiments, at least three segmentedelectrodes 230 in a set are utilized to allow for true 360° selectivity.

As previously indicated, the foregoing configurations may also be usedwhile utilizing recording electrodes. In some embodiments, measurementdevices coupled to the muscles or other tissues stimulated by the targetneurons or a unit responsive to the patient or clinician can be coupledto the control unit or microdrive motor system. The measurement device,user, or clinician can indicate a response by the target muscles orother tissues to the stimulation or recording electrodes to furtheridentify the target neurons and facilitate positioning of thestimulation electrodes. For example, if the target neurons are directedto a muscle experiencing tremors, a measurement device can be used toobserve the muscle and indicate changes in tremor frequency or amplitudein response to stimulation of neurons. Alternatively, the patient orclinician may observe the muscle and provide feedback.

The reliability and durability of the lead will depend heavily on thedesign and method of manufacture. Fabrication techniques discussed belowprovide methods that can produce manufacturable and reliable leads.

When the lead 200 includes a plurality of sets of segmented electrodes230, it may be desirable to form the lead 200 such that correspondingelectrodes of different sets of segmented electrodes 230 are radiallyaligned with one another along the length of the lead 200 (see e.g., thesegmented electrodes 230 shown in FIG. 2). Radial alignment betweencorresponding electrodes of different sets of segmented electrodes 230along the length of the lead 200 may reduce uncertainty as to thelocation or orientation between corresponding segmented electrodes ofdifferent sets of segmented electrodes. Accordingly, it may bebeneficial to form electrode arrays such that corresponding electrodesof different sets of segmented electrodes along the length of the lead200 are radially aligned with one another and do not radially shift inrelation to one another during manufacturing of the lead 200.

FIG. 5 is a side view of another embodiment of the lead 200 having aplurality of sets of segmented electrodes. As shown in FIG. 5,individual electrodes in the two sets of segmented electrodes 230 arestaggered relative to one another along the length of the lead body 210.In some cases, the staggered positioning of corresponding electrodes ofdifferent sets of segmented electrodes along the length of the lead 200may be designed for a specific application.

Typically, the lead body is made of a transparent or translucentmaterial. It may be difficult to visually distinguish individualsegmented electrodes when the lead body is transparent or translucent.Visual identification of the segmented electrodes may be useful so thata practitioner can verify that the lead has segmented electrodes or toalign the segmented electrodes along a desired orientation forimplantation.

To facilitate visual identification of segmented electrodes, a portionof the lead body between or around the segmented electrodes can beopaque, preferably white or a light color. FIG. 6A is a side view of anembodiment of a lead 600 with segmented electrodes 630 and ringelectrodes 620 along the length of a lead body 610. A portion 640 of thelead body 610 between the electrodes 630, 620 is made of an opaquematerial so that the segmented electrodes 630 can be visuallyidentified. The remainder of the lead body (i.e., the portions notcross-hatched in FIG. 6) can be transparent or translucent. The opacityof the portion 640 of the lead body may be limited to the surface of thelead body in portion 640 or may extend partially or completely throughportion 640 of the lead body.

The opacity of portion 640 of the lead body may be generated usingmaterials or processing techniques or combinations thereof. For example,the portion 640 of the lead body may include a biocompatible colorant orother opaque material, such as, for example, titanium dioxide, bariumsulfate, or white polyethylene. This colorant or other opaque materialmay be used in combination with other materials to form the lead body ormay be the sole material that forms the portion 640 of the lead body. Asanother example, the portion 640 of the lead body may be colored by aprocessing technique, such as laser marking or scoring, heating,grinding, or any combination thereof, to generate an opaque region.

Region 640 may have any suitable color. Preferably, the color of region640 is a light color, such as, for example, white, off-white, or apastel color. Preferably, the opaque region is less visibly reflectivethan the electrodes 630, 620 and, more preferably, the opaque region issubstantially non-reflective. In at least some embodiments, rougheningthe surface of the opaque region, such as grinding or scoring thesurface, may reduce reflectivity of the opaque region.

The region 640 of the lead body may have the same durometer or hardnessas other portions of the lead body, or the region 640 may have a higheror lower durometer or hardness compared to other portions of the leadbody.

The embodiment of FIG. 6A illustrates one example of an arrangement ofan opaque region with respect to segmented electrodes. In otherembodiments, more or less of the lead body may be opaque. FIG. 6Billustrates another embodiment in which a tip region 642 is also opaque.

FIG. 6C illustrates yet another embodiment in which the tip region 642and region 644 proximal to the electrodes 630, 620 is also opaque. FIG.6D illustrates a further embodiment in which only the region 646 betweenthe sets of segmented electrodes is opaque. FIG. 6E is yet anotherembodiment in which only the region 648 between segmented electrodes ofeach set is opaque. It will be understood that the embodiments of FIGS.6D and 6E can be combined so that both regions 646 and 648 are opaque.It will be further understood that the selection of opaque regionsillustrated in FIGS. 6A-6E can also be applied other arrangements ofsegmented electrodes and optional ring electrodes.

Another technique for indicating orientation or position of thesegmented electrodes includes providing a mark at or near the distal endof the lead, and distal to all of the electrodes, to indicate theposition of at least one of the segmented electrodes. As an example,FIGS. 7A and 7B illustrate leads 700 with segmented electrodes 730,optional ring electrodes 720, and a lead body 710. The lead 700 alsoincludes a marking 702 at the distal tip 704 of the lead that is alignedwith one of the segmented electrodes 730 a. This marking may also alignwith one of the segmented electrodes in two sets of segmentedelectrodes, as illustrated in FIGS. 7A and 7B. It will be recognizedthat the marking can be aligned, if desired, with electrodes in morethan two sets of segmented electrodes when the lead contains more thantwo sets.

The marking 702 may take any form including a circle (FIG. 7A), line(FIG. 7B), triangle, number, or any other regular or irregular shape orsymbol. The marking may be formed using a colorant provided during orafter formation of the lead body, an item inserted in the lead body, orby processing techniques such as, for example, laser scoring or marking,etching, grinding, or otherwise roughening the surface. A colorant maybe provided on the surface or within the lead body or any combinationthereof. The marking may be any suitable color, preferably, white,off-white, or some other light color. Optionally, the marking isradio-opaque.

In some embodiments, more than one marking is provided at the distal tipwith each marking aligned with a different segmented electrode orelectrodes. In some embodiments, a corresponding marking or markings maybe provided at the proximal end of the lead and aligned with the markingor markings at the distal end of the lead.

Other arrangements for marking the lead body can be used. FIG. 8A-8Fillustrate leads 800 with segmented electrodes 830, optional ringelectrodes 820, and a lead body 810. These leads include a stripe 850that extends along portions of the lead body near a distal end of thelead. The stripe is aligned with at least one segmented electrode andmay be aligned with a segmented electrode in two or more sets ofsegmented electrodes as illustrated in FIGS. 8A-8F. Optionally, thestripe may extend to a proximal portion of the lead and may even extendto, or near, a proximal end of the lead.

In FIG. 8A, the stripe 850 extends along the lead body 810 from a distaltip to a location proximal of the electrodes 820, 830 of the lead 800.In FIG. 8B, the stripe 850 extends from the distal tip to the mostproximal electrode 820 a. In FIG. 8C, the stripe 850 extends from themost distal electrode 820 b to a location proximal to the electrodes820, 830. In FIG. 8D, the stripe 850 extends proximally from the mostproximal electrode 820 a. In FIG. 8E, the stripe 850 extends from themost distal electrode 820 b to the most proximal electrode 820 a. InFIG. 8F, the strip 850 extends distally from the most distal electrode820 b and proximally from the most proximal electrode 820 a, but notbetween the electrodes.

The stripe may be formed using a colorant or by processing techniquessuch as, for example, laser scoring or marking, etching, grinding, orotherwise roughening the surface. A colorant may be provided on thesurface or within the lead body or any combination thereof. The stripemay be any suitable color, preferably, white, off-white, or some otherlight color. Optionally, the strip is radio-opaque.

In some embodiments, more than one stripe may be used. In suchembodiments, the different stripes may have different colors and areassociated with different segmented electrodes. For example, a lead mayhave a stripe of a first color associated with the first segmentedelectrode in one or more (or even all) sets of segmented electrodes andanother stripe of a second color associated with the second segmentedelectrode in one or more (or even all) sets of segmented electrodes.Additional stripes could be used for the third, fourth, or fifthelectrodes and so on.

Alternatively, instead of a stripe, a groove or notch may be used andpositioned at the same locations as stripe 850 in any of FIGS. 8A-8F.FIGS. 10A and 10B are schematic cross-sectional illustrations ofembodiments of a lead body 1010 with a groove or notch 1070 formed inthe exterior surface of the lead body. The groove or notch may be formedduring or after generation of the lead body. The groove or notch mayhave any cross-sectional shape including, but not limited, circular(e.g., FIG. 10A), square (e.g., FIG. 10B), triangular, and the like.Optionally, the groove or notch may be colored.

FIG. 9 illustrates a lead 900 with segmented electrode 930, optionalring electrodes 920, a lead body 910, and an indicator ring 960. Theindicator ring 960 is marked to indicate a particular segmentedelectrode or particular segmented electrodes in two or more sets ofsegmented electrodes. The indicator ring 960 may be marked in anysuitable manner including, but not limited to, scoring, etching,engraving, removing a portion of the ring, and the like. The indicatorring 960 may be made of any suitable biocompatible material includingmetals, polymers, and ceramics. The indicator ring may be radio-opaque.

The above specification, examples, and data provide a description of themanufacture and use of the composition of the invention. Since manyembodiments of the invention can be made without departing from thespirit and scope of the invention, the invention also resides in theclaims hereinafter appended.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. A stimulation lead, comprising: a lead bodycomprising a longitudinal surface, a distal end, and a proximal end; aplurality of electrodes disposed along the longitudinal surface of thelead body near the distal end of the lead body, the plurality ofelectrodes comprising a plurality of segmented electrodes, at least someof the segmented electrodes formed into a first set of segmentedelectrodes comprising at least two of the segmented electrodes disposedaround a circumference of the lead at a first longitudinal positionalong the lead, and a second set of segmented electrodes comprising atleast two of the segmented electrodes disposed around a circumference ofthe lead at a second longitudinal position along the lead, wherein thefirst and second set of segmented electrodes are adjacent to each otherand aligned with each other; and a marking disposed at or near thedistal end of the lead body and distal to all of the plurality ofelectrodes, wherein the marking is aligned with a one of the segmentedelectrodes.
 2. The stimulation lead of claim 1, wherein the markingcomprises an indicator ring disposed distal to the plurality ofelectrodes and marked to indicate alignment of a one of the segmentedelectrodes.
 3. The stimulation lead of claim 1, wherein the leadcomprises a plurality of the markings disposed at or near the distal endof the lead body and distal to all of the plurality of electrodes,wherein each of the markings is aligned with a different one of thesegmented electrodes.
 4. The stimulation lead of claim 1, wherein themarking comprises a colorant.
 5. The stimulation lead of claim 1,wherein the marking takes a form of a symbol.
 6. The stimulation lead ofclaim 5, wherein the symbol is a circle, triangle, or number.
 7. Thestimulation lead of claim 1, further comprising a corresponding markingdisposed at or near the proximal end of the lead body and aligned withthe marking disposed at or near the distal end of the lead body.
 8. Astimulation lead, comprising: a lead body comprising a longitudinalsurface, a distal end, and a proximal end; a plurality of electrodesdisposed along the longitudinal surface of the lead body near the distalend of the lead body, the plurality of electrodes comprising a pluralityof segmented electrodes, at least some of the segmented electrodesformed into a first set of segmented electrodes comprising at least twoof the segmented electrodes disposed around a circumference of the leadat a first longitudinal position along the lead, and a second set ofsegmented electrodes comprising at least two of the segmented electrodesdisposed around a circumference of the lead at a second longitudinalposition along the lead, wherein the first and second sets of segmentedelectrodes are adjacent to each other and aligned with each other; and astripe extending along at least a distal portion of the lead body andaligned with a one of the segmented electrodes in each of the first andsecond sets of segmented electrodes.
 9. The stimulation lead of claim 8,wherein the stripe extends from a distal end of the lead body.
 10. Thestimulation lead of claim 9, wherein the stripe extends from the distalend to a most proximal one of the plurality of electrodes.
 11. Thestimulation lead of claim 8, wherein the stripe extends only between theplurality of electrodes.
 12. The stimulation lead of claim 8, whereinthe stripe is disposed proximal to the plurality of electrodes.
 13. Thestimulation lead of claim 8, wherein the stripe extends to a proximalend of the lead.
 14. The stimulation lead of claim 8, wherein the stripecomprises a colorant.
 15. The stimulation lead of claim 8, wherein thelead comprises a plurality of the stripes extending along at least adistal portion of the lead body, wherein each stripe is aligned with adifferent one of the segmented electrodes.
 16. A stimulation lead,comprising: a lead body comprising a longitudinal surface, a distal end,and a proximal end; a plurality of electrodes disposed along thelongitudinal surface of the lead body near the distal end of the leadbody, the plurality of electrodes comprising a plurality of segmentedelectrodes, at least some of the segmented electrodes formed into afirst set of segmented electrodes comprising at least two of thesegmented electrodes disposed around a circumference of the lead at afirst longitudinal position along the lead, and a second set ofsegmented electrodes comprising at least two of the segmented electrodesdisposed around a circumference of the lead at a second longitudinalposition along the lead, wherein the first and second sets of segmentedelectrodes are adjacent to each other and aligned with each other; and agroove formed in the lead body and extending along at least a distalportion of the lead body, wherein the groove is aligned with a one ofthe segmented electrodes in each of the first and second sets ofsegmented electrodes.
 17. The stimulation lead of claim 16, wherein thegroove extends from a distal end of the lead body.
 18. The stimulationlead of claim 17, wherein the groove extends from the distal end to amost proximal one of the plurality of electrodes.
 19. The stimulationlead of claim 16, wherein the groove extends to a proximal end of thelead.
 20. The stimulation lead of claim 16, wherein the groove extendsonly between the plurality of electrodes.